GameSpot has an interesting quote from GameStop CEO Paul Raines, who describes their interest in getting into the (currently nonexistent) market for selling pre-owned digital content. "It’s very interesting," he said. "There are some technologies out there in Europe, and we’ve looked at a couple that are involved. We’re interested; it’s not a meaningful business yet. Right now we’re not seeing that as a huge market, but I think we’re on the leading edge. There are a few companies, a few start-ups, out there that we’ve talked to that are doing this."

Unless the publishers / developers say it can be transferred, it can not legally.

Which would be fine if courts in the EU hadn't just ruled that people have the right to resell their digital copies of software (wasn't aimed at games specifically, but very likely applies to them as well).

If the courts say it is legal, you don't need the publishers'/developers' permission.